1. Field of the Invention
This invention relates to superconducting microstrip transmission lines and to infrared radiation detectors fashioned from these microstrip transmission lines.
2. Description of the Prior Art
Infrared radiation detectors, used both as individual sensors and as elements in infrared sensing arrays, are used in a wide variety of applications. Superconducting infrared sensors have significant advantages over the more commonplace semiconducting infrared sensors. These advantages include a lack of Johnson noise, and superior optical and thermal hardness. It is desired to make such superconducting infrared sensors out of the new high critical temperature T.sub.c superconducting oxides, since they can be operated at relatively high temperatures.
Highly sensitive superconducting infrared sensors can be made from Josephson junctions. However, it is very difficult to process the new high T.sub.c superconducting oxides into Josephson Junctions. The high T.sub.c oxides are just beginning to be made into Josephson junctions.
Stripline structures made from high T.sub.c superconductors have been used as infrared sensors. These structures are easier to produce than Josephson junctions. A stripline structure comprises a dielectric substrate with a superconducting transmission line on the substrate, and two ground planes sandwiching the substrate. A problem with these structures is their relatively low sensitivity. In a stripline detector, the infrared radiation to be detected shines on the ground plane, where the field in the structure is at its lowest. This low field results in a low detection signal.